[RFC PATCH 02/10] C-SKY: TLS support

[Mao Han <han_mao at c-sky dot com>]

This patch implements TLS support for C-SKY. We support all four
standard TLS addressing modes (LE, IE, LD, and GD) when running on
Linux via NPTL.

        *sysdeps/csky/dl-tls.h: New file
        *sysdeps/csky/libc-tls.c: New file
        *sysdeps/csky/nptl/tcb-offsets.sym: New file
        *sysdeps/csky/nptl/tls.h: New file
        *sysdeps/csky/stackinfo.h: New file

Signed-off-by: Mao Han <han_mao@c-sky.com>
---
 sysdeps/csky/dl-tls.h             |  26 ++++++
 sysdeps/csky/libc-tls.c           |  32 ++++++++
 sysdeps/csky/nptl/tcb-offsets.sym |  10 +++
 sysdeps/csky/nptl/tls.h           | 169 ++++++++++++++++++++++++++++++++++++++
 sysdeps/csky/stackinfo.h          |  32 ++++++++
 5 files changed, 269 insertions(+)
 create mode 100644 sysdeps/csky/dl-tls.h
 create mode 100644 sysdeps/csky/libc-tls.c
 create mode 100644 sysdeps/csky/nptl/tcb-offsets.sym
 create mode 100644 sysdeps/csky/nptl/tls.h
 create mode 100644 sysdeps/csky/stackinfo.h

diff --git a/sysdeps/csky/dl-tls.h b/sysdeps/csky/dl-tls.h
new file mode 100644
index 0000000..d44fc18
--- /dev/null
+++ b/sysdeps/csky/dl-tls.h
@@ -0,0 +1,26 @@
+/* Thread-local storage handling in the ELF dynamic linker.  C-SKY version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Type used for the representation of TLS information in the GOT.  */
+typedef struct
+{
+  unsigned long int ti_module;
+  unsigned long int ti_offset;
+} tls_index;
+
+extern void *__tls_get_addr (tls_index *ti);
diff --git a/sysdeps/csky/libc-tls.c b/sysdeps/csky/libc-tls.c
new file mode 100644
index 0000000..30baf62
--- /dev/null
+++ b/sysdeps/csky/libc-tls.c
@@ -0,0 +1,32 @@
+/* Thread-local storage handling in the ELF dynamic linker.  C-SKY version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <csu/libc-tls.c>
+#include <dl-tls.h>
+
+/* On C-SKY, linker optimizations are not required, so __tls_get_addr
+   can be called even in statically linked binaries.  In this case module
+   must be always 1 and PT_TLS segment exist in the binary, otherwise it
+   would not link.  */
+
+void *
+__tls_get_addr (tls_index *ti)
+{
+  dtv_t *dtv = THREAD_DTV ();
+  return (char *) dtv[1].pointer.val + ti->ti_offset;
+}
diff --git a/sysdeps/csky/nptl/tcb-offsets.sym b/sysdeps/csky/nptl/tcb-offsets.sym
new file mode 100644
index 0000000..bf9c0a1
--- /dev/null
+++ b/sysdeps/csky/nptl/tcb-offsets.sym
@@ -0,0 +1,10 @@
+#include <sysdep.h>
+#include <tls.h>
+
+--
+
+-- Derive offsets relative to the thread register.
+#define thread_offsetof(mem)	(long)(offsetof(struct pthread, mem) - sizeof(struct pthread))
+
+MULTIPLE_THREADS_OFFSET		thread_offsetof (header.multiple_threads)
+TID_OFFSET			thread_offsetof (tid)
diff --git a/sysdeps/csky/nptl/tls.h b/sysdeps/csky/nptl/tls.h
new file mode 100644
index 0000000..69fadad
--- /dev/null
+++ b/sysdeps/csky/nptl/tls.h
@@ -0,0 +1,169 @@
+/* Definitions for thread-local data handling.  NPTL/csky version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _TLS_H
+#define _TLS_H 1
+
+#ifndef __ASSEMBLER__
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <dl-dtv.h>
+
+#ifdef __CSKYABIV2__
+/* define r31 as thread pointer register. */
+#define READ_THREAD_POINTER() \
+    ({ void *__result;						\
+       __asm__ __volatile__ ("mov %0, r31"			\
+                             : "=r" (__result));		\
+       __result; })
+#else
+#define READ_THREAD_POINTER() \
+    ({ register unsigned int __result __asm__("a0");		\
+       __asm__ __volatile__ ("trap 3;"				\
+                             : "=r" (__result) : : );		\
+       __result; })
+#endif
+
+#else /* __ASSEMBLER__ */
+#include <tcb-offsets.h>
+#ifdef __CSKYABIV2__
+/* define r31 as thread pointer register. */
+#define READ_THREAD_POINTER() \
+       mov r0, r31;	           
+#else
+#define READ_THREAD_POINTER() \
+       trap 3;             
+#endif
+#endif /* __ASSEMBLER__ */
+
+#ifndef __ASSEMBLER__
+
+/* Get system call information.  */
+#include <sysdep.h>
+
+/* The TP points to the start of the thread blocks.  */
+#define TLS_DTV_AT_TP	1
+#define TLS_TCB_AT_TP	0
+
+/* Get the thread descriptor definition.  */
+#include <nptl/descr.h>
+
+typedef struct
+{
+  dtv_t *dtv;
+  void *private;
+} tcbhead_t;
+
+/* This is the size of the initial TCB.  */
+#define TLS_INIT_TCB_SIZE	sizeof (tcbhead_t)
+
+/* Alignment requirements for the initial TCB.  */
+#define TLS_INIT_TCB_ALIGN	8
+
+/* This is the size of the TCB.  */
+#define TLS_TCB_SIZE		sizeof (tcbhead_t)
+
+/* Alignment requirements for the TCB.  */
+#define TLS_TCB_ALIGN		8
+
+/* This is the size we need before TCB.  */
+#define TLS_PRE_TCB_SIZE	sizeof (struct pthread)
+
+/* The thread pointer tp points to the end of the TCB.
+   The pthread_descr structure is immediately in front of the TCB.  */
+#define TLS_TCB_OFFSET		0
+
+/* Install the dtv pointer.  The pointer passed is to the element with
+   index -1 which contain the length.  */
+#define INSTALL_DTV(tcbp, dtvp) \
+  (((tcbhead_t *) (tcbp))->dtv = (dtvp) + 1)
+
+/* Install new dtv for current thread.  */
+#define INSTALL_NEW_DTV(dtv) \
+  (THREAD_DTV() = (dtv))
+
+/* Return dtv of given thread descriptor.  */
+#define GET_DTV(tcbp) \
+  (((tcbhead_t *) (tcbp))->dtv)
+
+#define TLS_DEFINE_INIT_TP(tp, pd) void *tp = (pd) + 1
+
+/* Code to initially initialize the thread pointer.  This might need
+   special attention since 'errno' is not yet available and if the
+   operation can cause a failure 'errno' must not be touched.  */
+#define TLS_INIT_TP(tcbp) \
+  ({ INTERNAL_SYSCALL_DECL (err);					\
+     long result_var;							\
+     result_var = INTERNAL_SYSCALL (set_thread_area, err, 1,		\
+                    (char *) (tcbp) + TLS_TCB_OFFSET);			\
+     INTERNAL_SYSCALL_ERROR_P (result_var, err)				\
+       ? "unknown error" : NULL; })
+
+/* Return the address of the dtv for the current thread.  */
+#define THREAD_DTV() \
+  (((tcbhead_t *) (READ_THREAD_POINTER () - TLS_TCB_OFFSET))->dtv)
+
+/* Return the thread descriptor for the current thread.  */
+#undef THREAD_SELF
+#define THREAD_SELF \
+ ((struct pthread *) (READ_THREAD_POINTER ()				\
+              - TLS_TCB_OFFSET - TLS_PRE_TCB_SIZE))
+
+/* Magic for libthread_db to know how to do THREAD_SELF.  */
+#define DB_THREAD_SELF \
+  CONST_THREAD_AREA (32, sizeof (struct pthread))
+
+/* Access to data in the thread descriptor is easy.  */
+#define THREAD_GETMEM(descr, member) \
+  descr->member
+#define THREAD_GETMEM_NC(descr, member, idx) \
+  descr->member[idx]
+#define THREAD_SETMEM(descr, member, value) \
+  descr->member = (value)
+#define THREAD_SETMEM_NC(descr, member, idx, value) \
+  descr->member[idx] = (value)
+
+/* Get and set the global scope generation counter in struct pthread.  */
+#define THREAD_GSCOPE_IN_TCB      1
+#define THREAD_GSCOPE_FLAG_UNUSED 0
+#define THREAD_GSCOPE_FLAG_USED   1
+#define THREAD_GSCOPE_FLAG_WAIT   2
+#define THREAD_GSCOPE_RESET_FLAG() \
+  do										\
+    { int __res									\
+	= atomic_exchange_rel (&THREAD_SELF->header.gscope_flag,		\
+			       THREAD_GSCOPE_FLAG_UNUSED);			\
+      if (__res == THREAD_GSCOPE_FLAG_WAIT)					\
+	lll_futex_wake (&THREAD_SELF->header.gscope_flag, 1, LLL_PRIVATE); 	\
+    }										\
+  while (0)
+#define THREAD_GSCOPE_SET_FLAG() \
+  do										\
+    {										\
+      THREAD_SELF->header.gscope_flag = THREAD_GSCOPE_FLAG_USED;		\
+      atomic_write_barrier ();						    	\
+    }									    	\
+  while (0)
+#define THREAD_GSCOPE_WAIT() \
+  GL(dl_wait_lookup_done) ()
+
+#endif /* __ASSEMBLER__ */
+
+#endif	/* tls.h */
diff --git a/sysdeps/csky/stackinfo.h b/sysdeps/csky/stackinfo.h
new file mode 100644
index 0000000..7b5eb65
--- /dev/null
+++ b/sysdeps/csky/stackinfo.h
@@ -0,0 +1,32 @@
+/* This file contains a bit of information about the stack allocation
+   of the processor.  C-SKY version.
+   Copyright (C) 2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _STACKINFO_H
+#define _STACKINFO_H	1
+
+#include <elf.h>
+
+/* On C-SKY the stack grows down.  */
+#define _STACK_GROWS_DOWN	1
+
+/* Default to an executable stack.  PF_X can be overridden if PT_GNU_STACK is
+ * present, but it is presumed absent.  */
+#define DEFAULT_STACK_PERMS (PF_R|PF_W|PF_X)
+
+#endif	/* stackinfo.h */
-- 
2.7.4